The following is the a distilled version of the Frequently Asked Questions and discussions (FAQ) about

Z car Body and Interior

as discussed on the Internet Z car club.

[The Internet Z car club is an international mailing list with over 125 members and
transmitted to a member's computer account over the internet.]
All information published here is the property of the original authors who are members of
The IZCC and may not be reproduced for commercial purposes Everything stated here is
based on the experiences and opinions of the original authors. The authors and editor
accept no responsibility for any damages arising from use of this information. Always consult
your workshop manual and take appropriate precautions when working on the car. If in doubt
consult a specialist.

Q: How Do I get rid of the tinny sound when closing the doors on my
car?

After stripping all the inside panels to make sure there is no rust
working its way out, I've filled all the empty body cavities with aerosol
foam, the kind you buy as weatherstripping in a can. And I've applied
sound deadening material to all flat surfaces where it won't show.
Especially in the doors. Balkamp (available at NAPA) makes some nifty
fibreglass filled, adhesive backed rubber sound absorbing mats. You
simply cut them to fit, heat with a heat gun and apply. My doors now
close with as nice a "thunk" as my BMW. And it no longer sounds like
someone is beating the shock towers with a hammer every time I hit a
sharp bump.

Pull the body work off in the back or simply pull the quarter panel
off in front. If there is ANY rust showing, it MUST be removed down to
bare, shiny metal. I use a sand blaster to strip down to metal and then
pickle the metal with phosphoric acid which will etch the last of the rust
that might remain in the grain of the metal and then passivates the
surface. I then spray it with a cold galvanising spray paint. I especially like
the LPS brand. Following that goes a very heavy coat of body
undercoating. The stuff in the aerosol cans is fine. Just be sure to apply
several coats and allow each to dry thoroughly in between. I use a heat
gun directed into the space to speed the cure.

After all this is done, only then should the foam be applied. Be sure
and don't block any drainage paths from internal body panels. You can
install tygon tubing to provide a positive path for the flow.

Sound deadening panels are made by Balkamp, Inc and sold under
the NAPA brand and can be used in place of the foam. The NAPA part
number is 825-6300. The package contains 6 - 12" X 12" panels anc cost
$19 - $25 I used 5 panels to completely deaden both doors on my Z. A
little goes a long way.

Q: Does a 240Z body need strengthening?

I had a U shaped piece of steel channel welded the length of the
two frame rails running underneath the passenger compartment. I also
have a roll bar bolting the rear wheel wells together. From places like
Motorsport Auto, you can get a strut bar that bolts the two shock towers
together. These bars are available for the front and rear shock towers.
The front one swings out of the way with the removal of a bolt.

Q: What Can I do about the Rusted Frame Rails on My Car?

As it turns out, Motorsport (and undoubtedly others) sells frame
rails. Actually, inspecting the floorpan and rail, it doesn't seem all that
impossible to chisel the old one off and weld the new on --- strip carpet,
seat, etc out before starting, no stitch welds, of course, careful with the
heat. There was an article in the Z-club newsletter a few years ago in
frame rail replacement or reinforcement. The recommendation to start with
channel steel or channel iron, cut it to fit and weld it over the old rails.

The difference between channel steel and channel iron is that
channel steel is made by forming heavy gauge steel over a mandrel while
channel iron is extruded or rolled from ingots. Channel steel is much
lighter. Channel steel is sometimes known as "conveyer channel" because
it is commonly used as the frame for roller-type conveyer belts. In fact, an
industrial conveyor supply company is a good source of the stuff. It cuts
easily, welds well and is strong. It can be gotten in galvanised which is
very desirable up North. To weld galvanised, simply peel off a tiny strip
of galvanise around the weld spots with a grinder. Then MIG the weld
which uses little heat so the adjacent metal is not heated enough to burn
the galvanise. Then coat the weld with LPS Cold Galvanise spray. Be
sure and weld plates on the ends or if you engage in off-road excursions,
you can pack the rails with many kilos of mud.

Q: What do I do about the rust holes on the inside walls of the front
wheel wells?

The front of the frame rail comes out from under the floorpan and
dead-ends just behind the front suspension, just far enough to attach one
end of a longitudinal suspension positioning rod (Compression rod). The
bottom of the inner fender sheet metal is welded to the rail. Actually, the
bottom of the inner fender is formed into another box atop the rail. It buts
against the bottom of the firewall, presumably to strengthen that `joint'.
From the outside you don't really notice it, you have to compare the
engine side and the wheel well side to realise there's a box there. For
lack of a better name, I'll call this `box'. About the middle of the box on
the outside, there is a slight peculiar warp as the frame narrows for the
wheel well. On mine, on both sides, there was a patch.

Anyway, the patch was rusting through on both sides of the car. As
near as I can figure, and a body-shop friend of mine agrees -- but we
accept NO liability!!! -- this is a `semi-' structural area. That is, it has
importance for strength and rigidity but isn't a keystone. Which means you
can patch it if you take a little care.

What I did was chisel the patch off and cut away any remaining
rusted metal. This opened into the box that I mentioned. I was surprised
that the inside of the box was fairly rust free, even though the hole was
certainly porous. So I really don't know WHY it rusts there. I cleaned out
whatever crap was in there. Since it seemed OK, and I didn't have the
time at the shop, I didn't use any special rust treatment, but anything that
wont catch on fire with welding would be a good idea (ie DON'T spray
undercoating!). This is a good time to mention that the fuel lines are
attached to the engine side of the passenger side box -- ie. 3" away from
where you're grinding, cutting, welding. [I removed the screw on the
bracket and slid a sheet of metal between as an extra shield]

So then I cut some sheet metal with about 1/2" overlap for whatever
hole I ended up with. I bent a lip for the bottom since the inner fender &
rail meet in a sort of `flange'. I MIG welded it with welds ~1/4" long every
2" or so, but alternating -- one here, one over there, then one 2" from the
first one, etc. You don't want to get the bulk of the box any hotter than
necessary or you'll weaken it. I assume that my patch provides little if any
strength, it just seals it. A good trick is to tack it in a couple of places and
while its hot, hammer it down to the shape of the box.

After that, a coat of primer. Since I didn't weld the whole seam, I
caulked it with seam sealer to minimise moisture getting into the box. A
heavy coat of rubberised undercoating strategically applied and you have
to look hard to see that it's even been repaired!

Q: Are you troubled by the analog clock not working in your Z?

If so, you can get a rebuilt one from MotorSport, on exchange, or
you may be able to fix it yourself! My 240's clock stopped long ago. Last
weekend, while doing other work, I had the centre portion of the dash out.
I decided to pull the clock while I had easy access. Once the clock is
removed, there are two small phillips head screws on the back side of the
black bezel. Removing these screws allows the removal of the bezel, set
knob, and lens. The knob stays attached.

Be very careful not damage the hands. I removed the hands, but
that may not be necessary. With the hands removed, you can remove the
face. Do not lose the washer and "spring" that sit on the shaft behind the
face. On the back of the housing, there are three nuts. Removing these
nuts allows the works to come out of the housing. Do not pull the wires
out of the housing, the hole is to small with the connectors on the ends.

The clock runs by means of an electric motor. This motor is held in
place by one small phillips screw and one stand off type post. The wires
are held by one clamp held in palace by a stand off post, and a solder lug
held by another stand off post. These posts are what the nuts on the
outside of the housing were attached to. Carefully remove the motor and
attached wires. Test the motor with a known good 12 volt source. The
male connector is the positive one. If the motor runs, the clock is probably
useable.

There is a plastic cover blocking access to one side of the internals,
ie gears, springs, do-hickeys, etc. Remove this cover to gain better
access. I do not recommend further disassembly, unless you are very
good at remembering where lots of small parts go, or are a watch repair
person by trade or hobby.

Very carefully blow out any dirt or dust from the works. Using a
suitable applicator, such as a toothpick, apply a light weight oil, such a
sewing machine oil, to all accessible friction surfaces. Reinstall motor.
Test clock while it is still hanging out of the housing. The clock should
work, if not, try and see if anything is hanging up. There is a small
sawtooth type gear that requires a SMALL amount of grease. If none of
the above works, you may want to take it to a watch/clock repair shop, or
order one from MotorSport, or last, but not least, buy a used one from
another Z.

If all is well, reassemble clock, as Datsun would say, assembly is
in reverse order of disassembly. Reinstall clock. If the clock works, enjoy!
If not,it was worth a try, anyway.

Q: Can I adjust the Clock in my Z so it keeps better time?

The Z clocks are adjustable -- at least in '75 they were.
Unfortunately you pretty much have to take it out to adjust it. Since
adjusting these things takes some time, what I did was clip it onto the
battery of my trusty Valiant (it's good for things like this!) with some
jumpers. Then every day before work, I'd check it against my watch.
tweak it in the appropriate direction then reset it. There's a hole in the
back of the clock casing opening to a small screw. It's marked to show
which way to speed up or slow down.

I eventually got it pretty close. For some reason though, it's off
again a few minutes every few weeks. Maybe cleaning out and (lightly)
oiling it would help?

One minor gotcha is that there's a flap of rubber hanging from the
vent panel which I assume is to cover up a mismeasurement by some
engineer. You want to stick that down behind the radio face as you put
the cover in.

Q: Can I tow a small (about 500 lbs total) motorcycle trailer.

It should do just fine. I regularly used tow a package that weighs
about 2000 lbs (two touring bikes plus very rugged homemade trailer.
You're going to have to pay attention to babying the clutch but that
applies to most any manual shift. I'd recommend installing an inertial
electric brake if you go much above 500 lbs. Makes controlling the
package much easier. The inertial brakes require no brake modifications
and consists of a small box that uses a pendulum to actuate the trailer
electric brakes. Northern Hydraulic has backfit electric brake kits available
for just about any trailer. Figure about $60 for the controller and about the
same for a brake kit.

I've also towed a dual axle trailer loaded with 4 tons of concrete
block, mortar mix and sand but that's another story. (You cannot imagine
how far that trailer can push a Z with all 4 wheels locked.

I bought my hitch at the local auto parts store and installed it myself.
If all else fails, you might try one of the U-Haul HitchWorld stores.

Q: Is it normal for a Z car front end to raise up at higher speeds?

As far as I know this is absolutely normal. As I recall, R+T or C+D
once did an article in which they measured the effectiveness of various
spoilers (including home made). They used a Z for their tests. In stock
form it generated quite a bit of lift. My old race Z had a huge front air dam
and a small (all that was allowed) rear spoiler. Spoilers are a big help, but
the spoilers must be mounted solidly. There is a trade off between drag
and down force that also must be considered before you determine the
angle of attack of your spoiler. Reams have been written on this subject.

Ride height and suspension condition will also greatly effect how
your car feels and responds at speed. If the nose is already high and the
suspension underdamped any bump will feel pretty scary.

Q: How do I go about installing a front spoiler? What is available?

Motorsport caries two flavours of plastic replacement parts.
'fibreglass' and 'urethane', reading between the lines, I gather that the
glass parts are manufactured by motorsport, while the urethane parts are
made elsewhere (Xenon?). Both are designed to replace the stock front
valance on the car.

A stock three piece metal replacement is ~$200. The plastic parts
are about half that. They are also available from Kaminari in a model that
fits over the existing metal. They mount by just installing about 6 screws
through the new spoiler to the old sheet metal. They leave a bit of a seam
showing just behind the bumper. You will have trouble (I was told by
Kamai) trying to fibreglass or bondo the seams (will crack regularly), so
I never tried. There is only a 2 inch seam that shows just behind the
bumper anyway. Those that replace the front metal are much better,
though slightly more expensive, and a bit more difficult to put on.

If you are installing a spoiler, before painting it, sand it with 400 grit
sandpaper first to rough up the surface. The primer will stick much better
than to the original smooth surface. Most have sufficient ground clearance
to clear the common curb, but some also drop much lower.

Q: Is there a way to fix the door locks on my Z car?

On mine (both the current car and previous one) they wouldn't
unlock properly. Like the pull knob inside would just barely reach the top
of the throw when you unlocked them with the key. $200 for a full new set
from Nissan was out of the question (for me). I removed the metal bracket
that connects from the back of the door lock itself (remove a small clip)
that connects to the rest of the mechanism. The problem is that the lock
unit uses a fairly soft pot metal and after so many thousand uses, wears
away. You can't replace the metal on the lock mechanism so I had a
friend put a spot of welding on the metal bracket to add some extra metal
on the bracket to replace what was worn away on the lock itself. I filed it
down flat, leaving a bit more metal in the inside diameter cam for the lock.
I have thus far done this on both of the Z Cars that I have owned recently
and the mod works great. Don't have to buy new door locks.

Q: What can be done about the rusty sheet metal on the Z car? I have
played with 2 rusty Z's plus other vehicles and found:

If the rust is through the metal, the only sure fix is to cut out the
rusted parts and weld in new metal. Sorry, it's extreme but there doesn't
seem to be a way around it. I have cut out metal and welded on new
using rented a welder. Be sure to rustproof the inside of the new metal
after it is installed.

If it is surface rust, you must get all of the rust neutralised in some
way or another. I have had good luck with "Ditzler Metal Prep". This is a
product that is used when you are down to bare metal in a repaint job,
you mix it with water and spread it over the bare metal to take out any
oxidisation (which occurs when any bare metal is exposed to the
atmosphere). I'll generally use it full strength on the rust with a wire brush
to get 90+% of the rust out (somewhat time consuming) and then use
another product called "Rust Mort" to transform the remaining rust deep
in the pits to a neutral compound. These products are available at many
auto body paint supplies houses.

I found that the only completely fool proof method to stop rust was
to sand blast the area and get rid of all the rust completely, then paint it
with a zinc based paint. (I used a paint that contained ~99% Zinc that
worked fine, unfortunately I don't remember the brand name or anything)

The result will be a surface that is as rust proof as if you had it
galvanised. Sand blasting is the superior way of removing rust as it does
not really hurt the soft metal, but when the sand hits the rust which is
significantly harder, it just kills that rust. You can get these little sand
blasting guns that blasts an area about as big as a nickel without spraying
the sand all over your garage. (It recycles the sand in a little bag)

Q: Should I use bondo in repairing my car?

CONs: Never use Bondo on a car you plan on keeping! Its "ok" for
small holes that can be painted over VERY well and have about 0 chance
of coming in contact with water, but for anything else its a killer. My car
has a lot of rust on it (I didn't pay much for it) or had anyway, I figure
about most of it would have been 1/2 as bad if the fool owner hadn't tried
to "fix" it with Bondo. If he had just left it, I'm sure it would have been a
lot better... he just slapped the bondo over the rust and put a coat of
cheap paint over... Bondo holds water...its porous. It will promote rust and
eat holes in your car if it gets wet... it will do it FAST. Don't use it. Use
steel sheets, or even aluminium sheets in non-structural areas I am still
having nightmares about some bondo I didn't find and finding a hole right
through the car where it was... I find some every once in a while, if that
owner hadn't moved to parts unknown, I'd have loved to strangle him for
his stupidity. If he had just neglected it, it would have been in better
shape.

PROs: He complained about bondo, but condoned (sort of) riveting
in sheet metal. I'd say both can be used in the right circumstances if used
correctly. Regarding bondo, I don't think it is such a great sin, in and of
itself. Sure, I'd prefer to learn how to straighten metal perfectly with a
torch, but that will come later. I certainly cant afford to pay a pro to do it!!!
The key with bondo is its _filler_ no more no less. You use it to level &
smooth the metal, but not to close it up. There has to be _NO_ access of
air or water to the `back' side of the bondo. And you seal the front side
with primer & paint. Providing it's no more than 1/8" max, It really
shouldn't be a problem. Bondo over rust is pure idiocy, though. Riveting
is kinda tricky for a road car, because it doesn't seal the two sheets
together. Unless maybe if you finish the seam with lead. Otherwise you've
got to seal both sides and end up with a pocket in between. For outer
body, you get bondo on one side and undercoating on the other. Iffy at
best. For underbody, maybe you can do ok with seam sealer - I'd try to
work the stuff into the seam real hard. (actually, I'd rather weld).

Q: Do Rust Converter chemicals work?

Someone else commented on Rust converter. My experience with
that has been mixed. At least I think I conclude that whereas they claim
it is water tight, it's apparently not. I had stuff treated with that that
re-rusted before I finished them. On the other hand, I did use it as last
resort in places I couldn't completely de-rust. I then drenched the areas
with undercoating and they've held. On my next project, I'll have a
sand blaster; my motto is (or will be) If there's rust there it'll get you.
Remove it, don't hide it.

If it's holes, you've gotta replace sheet metal. As somebody else
pointed out, you can get replacement floor panels. It depends how
"serious" the rust is as to whether it's worth it. Put your car up on jack
stands, get comfortable on you're crawler, turn up the radio and spend an
afternoon inspecting your underbody tip to tail. Make sure you don't get
any more surprises and you can better assess what you've got to do and
whether it'll be worth it.

Q: Does the "RustEvader" or "something" which "charges" a car body
to prevent rust?

Rust (cancer, rot) is an oxidation/reduction reaction. When there
are metals involved and charges you get a flow of electrons. All metals
are ranked on an electrochemical potential scale. When you have 2
different metals together, there is electron flow from the anode (-) to the
cathode (+). Along with this, the anode metal corrodes (disintegrates,
oxidises), which in the case of iron, is called rust.

The theory of the "RustEvader" is to pick a metal which is anodic
to steel -- this is called a "sacrificial anode" and it will be oxidised while
the car body is unharmed. Theory sounds good, and was used on ocean
(salts) going ship which had .. say copper rivets with iron hulls.

The problem with applying the same approach to car is that rust on
car is much more localised ox/red reaction. At each paint chip, you get a
local galvanic cell which will be its own circuit, which will not include the
sacrificial anode. In fact, on an atomic scale, alloys "rust" between atoms
within the lattice structure if there is some charge carrier (salts) and
different metals.

Paint, when intact seals out charge carriers (salts) thus preventing
the ox/red reaction, but ... when broken by chips allows local reactions
which will not be protected by the "sacrificial anode" because they are
very localised reactions. The aforementioned old boats are floating in the
charges (all metals are connected by contact to sea water) and therefore
the copper rivets can be saved by picking a more anodic metal than
copper (I think magnesium worked?) Enough said.

Q: How can I replace the front cross member that is damaged.

You should be able to get a cross member-control arm assembly in
the salvage (junk) yard. The easiest swap would be to unbolt the cross
member and control arms from the car, without undoing the control
arm-to-cross member attachment. This is only an option if the control arm
bushings in the scrap car's control arms are o.k. Doing it this way would
make the operation a bolting procedure only, with no pressing in and out
of the control arm bushings. But then again, the odds of finding this
assembly in the yards with good bushings are low.

While you're at it you ought to put in new control arm bushings any
way. If your's are original, I'll bet they're wasted. Go with polyurethane
bushings or Camber bushings (like the ones you describe for the rear) if
you want to gain camber/roll-centre/bump-steer adjustment. These parts
are available from many of the suppliers in the monthly z-car listing.

I mentioned bump steer above. This is inherent in the z-car, due to
a poorly placed control arm mounting bolt hole in the cross member. I've
seen a modification ( small $$ ) that says to correct this by:

Remove the doubler washer in the original cross member hole
with a chisel.

Drill a 9/16" hole in the cross member 3/4" above the
original hole.

Weld in a doubler plate for the new hole.

Grind the part
of the control arm near the bushing to prevent interference with the cross
member. [This is from a V-8 Z conversion manual.]

Q: How do I repair the Z-Car Door Hinge?

The door Hinges on the Drivers side of my '71 240Z were getting
worn out pretty bad. The end of the door, when opened, could be wiggled
up and down by more than an inch and when closing the door, it made
an unpleasant clunk as it tried to climb the striker plate in search of its
latched position.

Both hinges are accessible from the foot-well area after removing
the side kick panel. No need to remove the dash. (at least on my '71 240)
I decided it was time to repair or replace these hinges, so I pulled
the door off, removed the hinges, drove the hinge pins out and inspected
the parts. I discovered that the pins themselves were badly worn (had
about .050 inch worn off the contact area) and the bushings were only
slightly worn. I called the local Datsun dealer hoping I could buy just the
pins and bushings, but no luck. They only sold the hinges as assemblies
and they wanted about $110 for one doors worth. At this point I figured
that if I could just find a suitable replacement for the pin, I could
reassemble my hinges and they should work fine. I measured the Datsun
pins and they were 5\16 inch dia and 2 inches long. I headed into town
to our local bolt distributor (Hi-Strength Bolt CO) and sure enough, they
had 5/16 x 2 steel dowels (hardened and ground) for about $.50 each.

They only problem remaining was how to captivate the new pin. The
original pin had a straight knurl on one end to create an interference fit.
Since my new pins were already hardened, there wasn't much I could do
to them. So, I drilled and tapped one of the hinge halves for a 6-32 set
screw that would seat against the pin. I also ground a small flat on the pin
for the set screw to seat against.

I put everything back together, and the door feels a _lot_ better. Not
bad for about $2.00 worth of material.

Q: What can I put on my dash to keep it from cracking?

Armour All is a good one, but I used Vaseline on mine. Use a cloth
to put a very thin layer on it. Rub it in REALLY good. Then take a clean
cloth and wipe off all the residue.

Having followed rec.autos for a while and also having talked with
friends about it, it seems as Armour All works fine as long as you keep
applying it regularly. If you don't, the dashboard gets withdrawals and
cracks.

Porsche used to give new car owners a bottle of Armour all until
they found that it could lead to cracked dashes. I've heard that a product
called 301 is the one to use. It is available through some new car dealers.

I believe that the mail-order house Harrington sells this product as
well. I assume they're listed in the 800 directory. They tout it to be the
best thing on the planet and they say that it's what Porsche and other
high-end car manufacturers tell their customers to use.

I saw a Datsun service bulletin in the late 70's that attributed
dashboard cracking partially to Armour-All.

Q: IS there any alternative to replacing the pitted, yet otherwise straight
bumpers on my Z?

Rather than replace it, a friend with a 77 Z uses a flat black rubber
paint, I think that it is called "Dipit" or something like that. They sell a
product at some "farm" type stores and elsewhere that is a thick rubber,
you dip like the handles of tools in it and it dries... Well, they sell the
same stuff in a spray that looks super when sprayed on the bumper, and
it seems to stick quite well. As long as the metal is straight, a little rusty
is ok, it will turn out looking very nice. The black bumper can really add
a bit of class, especially on some colours like red, or white cars. Just an
idea. Beats $200 for a new bumper...

Q: How do I keep from bending the side metal on my car when I use
the scissor jack?

There is a bend back, running the length of the body between the
wheel wells, under the each side of the car that has a notch at each end
on 240's. The notch is a locater for the stock scissors jack saddle. I just
place a piece of 2x4, 18 inches long on top of my 2 ton hydraulic jack
saddle and place it length-wise on the bend back to raise each corner of
the car. Haven't had any problems since I started using this method (I too
dented the rails the first time I used them as jack points back in '70).

Q: What is a "Fairlady Z"?

The Z was introduced in Japan as the "Fairlady Z" it had a 2 Litre,
6 cyl engine (L20 series) that produced 130HP as compared to the 240Z's
150HP. Apparently there was some tax reason for limiting the size of the
engine for the Japanese market. A high performance version of the
Fairlady was also sold in Japan. This was the Fairlady 432 (a racing
version was designated the 432R). This engine was also 2 Litres, but had
4 valves per cyl, 3 carbs and 2 camshafts (hence the 432 designation)
and produced 160 HP. This engine was an S series and was designated
the S20. I don't know what the differences are between it and the L series
found in most other Datsuns.

There were only 420 of the Z432s manufactured during its 4 years
and all were sold in Japan. Some of them were used by the Japanese
Highway Patrol.

Q: What else can be done about a rusted under carriage?
I have a 73 240Z that used to live in Galveston so it has
accumulated some healthy rust in the undercarriage. It is getting to
the point that I'm a little concerned about body flex under driving
conditions the car seems to wander a bit more than I think it should.
Anybody out there had experience with attacking major rust
problems?

I've been through the floorboard rust problem TWICE on my 73 240
now. I'm presently redoing a botched job I did about 7 years ago.
Originally, I used 18 gauge flat sheet steel (scrap from a metal door
factory) which I cut and bent to cover large (1 -by- 3 ft) areas of the floor.
I did this while leaving a 1/2" to 3" overlap of the metal around the edges
of the holes I cut out of the floor. These were MIG welded every 3/4" or
so along the perimeter, top and bottom. I then used a caulk sealer to
"seal" the seam on top and bottom. Bad move. The caulk promoted rust
underneath and the metal in the overlap region rusted internally. I'm
having to go back and clean up the surface rust. I'm doing a continuous
weld around the perimeter on the top (inside) and grinding the overlap
metal on the underside back to the weld. This way I don't need a sealer
at all and the job looks much more professional. Not to mention being
stiffer. It is a little harder to weld continuously without burning through, but
not too bad.

I'm also replacing the "frame rail" that is spot welded to the
underside of the floor by completely removing the frame rail and floor
above it and replacing it with a 2"-by-3", .083" wall mild steel tube, which
connects to the 2-1/2" -by- 2-1/2", .094" wall frame rails I've installed in
the engine compartment and the rear sub frame behind the seats.

I guess you can tell I'm going hog wild here, replacing ALL the old
structural stuff and the metal on the firewall where the frame rails meet.
If you're not going to do it right and replace ALL the rusty stuff , don't do
it at all. Welding new metal to thin, rusty stuff isn't going to help the
stiffness problem you're having. (The reason I'm being extra sensitive to
stiffness is for the 327 Chevy V8 I'm installing. It's built and every thing
except exhaust and drive shaft are ready, but the car is still being
de-rusted and stiffened.)

Of course, I would strongly suggest finding another rustless car, if
you're not too attached to the one you have.

Q: How can I stop the plastic squeeks in the interior of my car ?

I sprayed the interior panels with silicon. You have to do it several
times a year, but it's not that much work to spray all the joints where
panels rub and wipe with a clean cloth. A can of silicon spray should be
under $3.00. The real fix would be to remove the panels and line the
points that rub with something smooth...like teflon tape.

you can also replaced the 'fuzzies" and weather strip, and much of
the plastic squeaks and rattles go away. 'course in Texas, the windows
are rolled down all the way anyway since the air conditioning isn't worth
a flip.

Q: How do I get more tire clearance for my oversize tires?

In my "gads-I-need-more-tire-clearance" days, I did the ole'
"hacksaw" method of cutting the lip every two inches towards the outside
then slowly and carefully hammering the lips upwards. It worked but
wasn't the most elegant way of doing it.

Use that method or try this one (thanks to a tip in the ipd (Volvo)
catalogue):

Using a pipe of sufficient strength and diameter, you can roll the lip
without cutting by inserting the pipe between the top of the tire and the
fender lip. Using heavy gloves, hold the pipe against the lip and roll the
car forward and backwards slowly, letting the tire apply most of the
pressure on the pipe and fender lip. Repeat until the lip is turned up as
far as you need. (Note: you may need to touch up the lip with new paint
as it will be cracked on the lip, but out of sight.)

Disclaimer: I have not tried this but it seems like it would work. Also,
be VERY careful doing this as it's a VERY dangerous looking task. I
would probably do this with a GOOD friend that you trust and NOT under
power...just a tad bit of gravity in the driveway.

Someone mentioned using a big piece pipe between the tire and
wheel well. Baseball bats work well too. I have seen this done before,
sometimes you need to put a lot of weight on the fender in order get
enough force on the bat. Having some friends sit on the car usually does
it. Take it slow and don't expect perfect results.